/Engine/Source/Editor/UnrealEd/Public/ImportUtils/StaticMeshImportUtils.h
This function is call before building the mesh when we do a re-import
namespace StaticMeshImportUtils { void StaticMeshImportUtils::RestoreExistingMeshSettings ( const [FExistingStaticMeshData](API\Editor\UnrealEd\ImportUtils\FExistingStaticMeshData) * ExistingMesh, [UStaticMesh](API\Runtime\Engine\Engine\UStaticMesh) * NewMesh, int32 LODIndex ) }